#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<cmath>
#include<map>
#include<set>
#include<cstdio>
#include<algorithm>
#define debug(a) cout<<#a<<"="<<a<<endl;
using namespace std;
const int maxn=2e5+1000;
typedef long long LL;
inline LL read(){LL x=0,f=1;char ch=getchar();	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
return x*f;}
vector<LL>g[maxn];
LL in[maxn],dep[maxn];
map<LL,LL>map1;
void dfs(LL u,LL fa){
     dep[u]=dep[fa]+1;
     for(LL i=0;i<g[u].size();i++){
         LL v=g[u][i];
         if(v==fa) continue;
         dfs(v,u);
     }
}
int main(void){
   cin.tie(0);std::ios::sync_with_stdio(false);
   LL n;cin>>n;
   for(LL i=1;i<n;i++){
       LL u,v;cin>>u>>v;
       g[u].push_back(v);
       g[v].push_back(u);
       in[v]++;in[u]++;
   }
   for(LL i=1;i<=n;i++){
       if(in[i]==2){
          cout<<"NO"<<"\n";
          return 0;
       }
   }
   cout<<"YES"<<"\n";
   return 0;
}
